A bag with an interlocking means attached to an inner surface around an opening of a bag main body to seal the opening such that it can be freely closed and reopened is widely used in various fields such as foods, drugs, sundries, and so on. In an example of the interlocking means, first and second interlocking parts, which are detachably interlocked with opposite surfaces of a pair of band-shaped bases, are provided in longitudinal directions of the bases.
For example, an interlocking means in which both the first interlocking part and the second interlocking part have a plurality of male hook parts running parallel to each other, and heads of the mutual male hook parts are inserted between two opposite female hook parts are mutually hooked to be attached/detached is known (Patent Document 1).
In this bag with an interlocking means, the first and second interlocking parts of the interlocking means are interlocked, and thereby the opening formed in the bag can be closed. The bag can be reopened by grasping opening ends of the bag main body to which the interlocking means is attached, pulling them away from each other, and releasing the interlocking between the first interlocking part and the second interlocking part.
When the opening is closed by the interlocking means in the bag with an interlocking means, the first and second interlocking parts are generally partly interlocked at a lateral end side of the bag first. Afterward, by holding the interlocked portion between one's fingers and sliding the fingers along the interlocking means, the first and second interlocking parts are continuously locked up to a lateral end of the opposite side. In this case, the first and second interlocking parts are interlocked at portions at which the first and second interlocking parts are interlocked first, which can be recognized with fingers by touch. However, it is difficult to recognize with fingers by touch whether or not interlocking is successful when the first and second interlocking parts are continuously interlocked by sliding the fingers. For this reason, the opening of the bag may be unintentionally left partly opened. If the interlocking between the first interlocking part and the second interlocking part is insufficient in portions, when the internal pressure of the bag is increased, the interlocking is partly released by the internal pressure, and the bag may open.
As a method for making it easy to recognize the interlocking between the first interlocking part and the second interlocking part with a sense of the fingers, a method for increasing interlocking strength between the first interlocking part and the second interlocking part is considered. However, as the interlocking strength increases, it is more difficult to interlock the first interlocking part and the second interlocking part, and a handling characteristic of the bag is reduced.
An interlocking means in which detachably interlocked male and female interlocking parts are provided on opposite surfaces of a pair of band-shaped bases in longitudinal directions of the bases, a plurality of cutout parts are formed in the male interlocking parts at intervals in a lengthwise direction, and thereby the male interlocking parts are discontinuous, is known (Patent Document 2). When the interlocking means is used, since the male interlocking parts become intermittent, it is possible to sense that the interlocking is happening with one's fingers when the male and female interlocking parts are continuously interlocked while sliding the fingers. However, in a bag with an interlocking means for which the interlocking means is provided, when liquid or powdered contents are stored, there is a problem that the contents leak out through the cutout parts of the male interlocking part.